Method of use for percutaneous material removal device and tip

ABSTRACT

A method of removing material from a body lumen in a patient in need of such removal, comprising advancing a catheter-mounted device having a distal material removal tip including a hollow housing and a member rotatable therewithin, rotating the rotatable member, drawing the material into the housing, shearing the material in the housing between relatively rotating shearing members to reduce the clogging propensity of the material, and removing the sheared material from within said housing as the material removal tip is advanced through the vessel. In another embodiment, the rotatable member of the invention includes grinding member for grinding the material prior to the contact of the material with the shearing member. An article of manufacture that includes packaging material and instructions in the method of the invention contained within the packaging material is also taught.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a Continuation-in-part, of application Ser. No. 09/308,038,filed Apr. 30, 1999 U.S. Pat. No. 6,238,405, which has been allowed forIssuance as a U.S. Letters Patent, and for which the issue fee has beenpaid, the entire disclosure of which is hereby expressly incorporatedherein by reference. Likewise, co-pending C-I-P, U.S. Ser. No.09/766,150 filed on Jan. 18, 2001, based upon the same parent, in thename of the same inventors, and assigned to instant assignee isexpressly incorporated herein by reference, in its entirety.

BACKGROUND OF THE INVENTION

The present invention is related to methods and apparatus for clearingblocked natural and synthetic vessels, and more specifically, to methodsand apparatus for percutaneously clearing material from vessels with arotating device and suction, without luminal damage.

A variety of techniques and instruments have been developed for use inthe removal or repair of obstructive material in vessels and other bodypassageways. Such material may include atheromas, thrombi, or emboli. Anatheroma is a mass of plaque of degenerated, thickened arterial intimaoccurring in atherosclerosis. A thrombus is an aggregation of bloodfactors, primarily platelets and fibrin with entrapment of cellularelements, frequently causing vascular obstruction at the point of itsformation. An embolus is a clot or other plug brought by the blood fromanother vessel and forced into a smaller one, thus obstructing thecirculation, generally.

Many catheter-mounted devices are presently available for removingmaterial from vessels. Some of these devices include rotatable abrasivemembers on the distal tip of a flexible catheter, which tend to removehardened atherosclerotic materials without damaging the normal elasticsoft tissue of the vessel wall. However, long standing needs remain.

Another material removal device is seen in the U.S. Pat. No. 5,423,799to Shiu, and includes a tubular housing mounted on the distal end of acatheter within which a helical screw member rotates. The screw includesa sharp edge which, in cooperation with housing, cuts the tissue anddraws it into the housing for later removal. Artisan recognizemaceration issues with the devices and methods practiced under thispatent.

Despite advances made in catheter-mounted material removal devices, manyof them remain limited in their operational capacity, and tend to clogup fairly quickly. This necessitates the surgeon advancing very slowlythrough the material blockage, and greatly increases the length ofsurgery. In the worst-case, the device becomes irreversibly clogged, andmust be removed and another device procured and substituted. Therefore,there remains a need for a more efficient catheter-mounted materialremoval device that can rapidly cut through a mass of blocking materialwithout clogging. Likewise, an interventionist—friendly method andapparatus method remain outstanding.

BRIEF SUMMARY OF THE INVENTION

In one embodiment, the present invention provides a device for removingmaterial from a body lumen including an elongate, flexible tube havingdistal and proximal ends and a passageway there through. The device hasa material removal tip on the distal end including an outer housingrotationally fixed with respect to the tube and a rotating member withinthe housing. The housing includes a lumen extending from a distal openmouth to the tube passageway. The rotating member includes distal andproximal ends, a central body, and a plurality of circumferentiallyspaced flanges extending radially outward from the body. At least oneshearing member is formed within the lumen of the housing and axiallyadjacent to the flange to cooperate with the flange and shear materialreceived in the housing mouth. The shearing member may be locateddistally or proximal with respect to the flanges, or shearing members onboth sides of the flanges may be provided. The housing desirablyincludes proximal and distal sections, each including lumens, and anannular groove larger than either the distal or proximal sections andformed therebetween for axially restraining the flanges on the rotatingmember. The shearing member is preferably located adjacent to thegroove. The housing may be formed in one piece or two separate pieces.

In a preferred embodiment, the rotating member has a central body and ahelical screw thread thereon and is driven by a drive shaft that extendsthrough a catheter attached to the housing. The shearing member has aradial dimension that brings it into close proximity with an associatedrotating member. That is, a distal shearing member is sized to come intoclose proximity with the central body of the rotating member, while aproximal shearing member is sized to come into close proximity with adrive shaft.

In another aspect, the present invention provides a material removal tipfor use in a catheter-mounted material removal device, comprising arotatable member having an outwardly projecting shearing member, and agenerally tubular housing sized to receive the rotatable member. Thehousing includes a stationary shearing member located axially adjacentto the rotating shearing member. The stationary and rotating shearingmembers cooperate to chop material received within the housing, reducingthe clogging propensity of the material. There is preferably a pluralityof rotating shearing members axially restrained within a groove formedon the inner surface of the housing. The stationary shearing member isdesirably located adjacent to groove, either proximally, distally, orboth in the case of two stationary shearing members.

The present invention further provides a method of material removal,including advancing through a body lumen a catheter-mounted materialremoval device having distal material removal tip including a hollowhousing and a rotatable member therewithin. The rotatable member isrotated to engage the material, which is then sheared in the housingbetween relatively rotating shearing members to reduce the cloggingpropensity of material. Subsequently, the sheared material is removedfrom within the housing as the device is further advanced through thebody lumen.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a hand-held material removal system withinwhich the material removal device of the present invention isincorporated;

FIG. 2a is a longitudinal sectional view through one embodiment of amaterial removal tip of the present invention having a two-piecehousing;

FIG. 2b is an end elevational view of the material removal tip having atwo-piece housing, taken along line 2 b—2 b of FIG. 2a;

FIG. 2c is a sectional view of a stationary shearing member of theproximal housing section in operation, taken along line 2 c—2 c of FIG.2b;

FIG. 2d is a sectional view of a stationary shearing member of thedistal housing section in operation, taken along line 2 d—2 d of FIG.2b;

FIG. 3a is a longitudinal sectional view through a proximal housingsection of the material removal tip of FIG. 2a;

FIG. 3b is an end elevational view of the proximal housing section,taken along line 3 b—3 b of FIG. 3a;

FIG. 4a is a longitudinal sectional view through a distal housingsection of the material removal tip of FIG. 2a;

FIG. 4b is an end elevational view of the distal housing section, takenalong line 4 b—4 b of FIG. 4a;

FIG. 5a is a longitudinal sectional view through a second embodiment ofa material removal tip of the present invention having a one-piecehousing;

FIG. 5b is an end elevational view of the material removal tip having aone-piece housing, taken along line 5 b—5 b of FIG. 5a;

FIG. 6a is a longitudinal sectional view through the one-piece housingof the material removal tip of FIG. 5a;

FIG. 6b is an end elevational view of the one-piece housing, taken alongline 6 b—6 b of FIG. 6a;

FIG. 7a is a longitudinal sectional view through an alternativeone-piece housing in accordance with the present invention;

FIG. 7b is an end elevational view of the alternative one-piece housing,taken along line 7 b—7 b of FIG. 7a;

FIG. 8a is a longitudinal sectional view through yet a still furtherembodiment of a material removal tip of the present invention whereinthe rotatable member includes a grinding means, according to the instantteachings, and,

FIG. 8b is an end elevational view of still yet another grinding meansof the present invention.

DETAILED DESCRIPTION

The present inventors have discovered an improved method forpercutaneous material to be made into small pieces and withdrawn fromaffected luminal spaces. Likewise, the instant teachings arephysician/interventionist—friendly and useful.

With reference to FIG. 1, a material removal system 10 suitable for usewith the present invention comprises an elongate flexible tube 12 havinga proximal end 14 and a distal end 16. A hand-held control 18 attachedto the proximal end 14 of the tube 12 permits manipulation of thesystem. The control 18 carries electronic circuitry, controls, andindicators. A source of vacuum 20 communicates with the hand-heldcontrol 18 which in turn includes passages for creating a negativepressure in the interior of the tube 12. In addition, a drive motor (notshown) is mounted within the hand-held control 18 for supplyingrotational motion to a flexible drive shaft 22 (FIG. 2a) extendingthrough the elongated tube 12. A tubular removal passageway 24 is thusdefined in the space outside of the drive shaft 22 and within theflexible tube 12. The drive shaft 22 is preferably hollow to permitpassage therethrough of a guidewire 28.

The present invention provides an improved distal material removal tip30, which is shown in detail in FIGS. 2, 3 and 4. The removal tip 30comprises an outer housing 32 and a member 34 received therewithin forrotation about an axis 37. The outer housing 32 has a substantiallyhollow tubular shape and comprises a distal section 36 and a proximalsection 38, through which a continuous lumen 40 extends. The lumen 40 isdefined by a distal lumen 42 within the distal section 36; a proximallumen 44 within the proximal section 38, and an annular groove 46located intermediate the distal and proximal sections, all being axiallyaligned. In the illustrated embodiment, the groove 46 has a largerdiameter than the distal lumen 42, which in turn has a larger diameterthan the proximal lumen 44. The rotatable member 34 is received withinthe distal housing section 36, with a portion within the groove 46, aswill be described below.

The aforementioned flexible tube 12 is seen in phantom coaxiallyreceived over a tubular body 50 on the proximal housing section 38.Likewise, the drive shaft 22 is seen in phantom extending through theflexible tube 12 and through the proximal lumen 44 into engagement withthe rotatable member 34. In this manner, the drive shaft 22 and member34 rotate together within the housing 32. A number of different driveshaft configurations may be utilized with the present invention, none ofwhich should be construed as limiting. Both the elongated tube 12 anddrive shaft 22 are seen in phantom in FIG. 2a, and thus are not seen inthe end view of FIG. 2b.

As mentioned, the rotatable member 34 is partly received within thegroove 46. More particular, the rotatable member 34 comprises agenerally cylindrical or tubular body 56 from which a continuous helicalscrew thread 58 radially outwardly extends. The screw thread 58 beginsat a distal face 60 of the member 34 and continues around the body 56for approximately two-thirds of its length. A plurality of cantileveredfingers 62 defined by longitudinal slots 64 are provided on the proximalend of the member 34. Each of the fingers 62 carries an outwardlyextending cutter or flange 66, each of which in axial projection has agenerally truncated triangular shape as seen in FIG. 2b. There arepreferably three such flanges 66 evenly circumferentially spaced andforming somewhat of a propeller configuration about the rotatable member34. The flanges 66 terminate in outer tips that together define a circlehaving a diameter greater than the diameter of the distal lumen 42, butless than the diameter of the groove 46.

With reference to FIGS. 3a and 3 b, the proximal housing section 38includes the tubular body 50 terminating on its distal end in a radiallyoutwardly extending annular shoulder 70 having a diameter that isreduced at a step 72 to a cylindrical land 74 ending at a distal face76.

And seen in FIGS. 4a and 4 b, the distal housing section 36 alsoincludes a tubular body 80 extending from a distal mouth 82 to aproximal end 84. The lumen 42 extends proximally from the mouth 82 untila step 86 increases the diameter to that of a stepped bore 88.

The land 74 of the proximal housing section 38 has a diameter that isapproximately equal to the diameter of the bore 88. Consequently, thedistal end of the proximal housing section 38 is closely received withinthe bore 88 until the proximal end 84 contacts the step 72. Bycooperation between the distal and proximal sections 36, 38, the groove46 is defined on its outer side by the bore 88, and on respective axialsides by the distal face 76 of the proximal housing section 38 and thestep 86 of the distal housing section 36. The rotatable member 34 iscaptured in the location of FIG. 2a by cooperation between the outwardlyprojecting flanges 66 and the groove 46. The cantilevered fingers 62enable inward deflection of the flanges 66 so that they can pass throughthe distal lumen 42 of the housing 32 and snap outward into the groove46. The spacing between the flanges 66 and the groove 46 are slightlyexaggerated in the drawings, and in a working model of the device theaxial dimension of the flanges 66 will be slightly smaller than thespacing between the step 86 and the distal face 76. In this manner, theflanges 66 are constrained in the groove 46 from even slight axialmovement.

The present invention provides at least one shearing member that isaxially adjacent the flanges 66. In the embodiment of FIGS. 2-4, thereare two such shearing members, a distal member 100 and a proximal member102. The distal shearing member 100 projects radially inwardly withrespect to the distal lumen 42 of the distal housing section 36.Likewise, proximal shearing member 102 projects radially inwardly withrespect to the proximal lumen 44 of the proximal housing section 38. Asseen best in FIG. 4a, the distal shearing member 100 has a proximal face104 which is co-extensive with the step 86. The proximal face 104 isthus positioned on the edge of the groove 46 closely adjacent to therotating flanges 66. In like manner, as seen in FIG. 3a, the proximalshearing member 102 has a distal face 106 which is co-extensive with thedistal face 76 of the proximal housing section 38. The distal face 106is thus positioned on the edge of the groove 46 closely adjacent to therotating flanges 66.

With reference to the detailed views of FIGS. 3-4, the shearing members100, 102 in a preferred embodiment resemble teeth. More specifically,the distal shearing member 100 includes an arcuate inner face 110 havinga relatively small included angle 112 and transition surfaces 114 oneither side joining the inner face to the distal lumen 42. The proximalshearing member 102 includes an arcuate inner face 120 having anincluded angle 122 and transition surfaces 124 on either side joiningthe inner face to the proximal lumen 44. The small included angles 112,122 and generally radially oriented transition surfaces 114, 124 defineshearing members 100, 102 of relatively small angular size. The angularsize must of course be sufficient to provide shearing strength inoperation, as will be described, but should be kept to a minimum toreduce the obstruction to flow of material through the housing 32.

As seen in FIG. 2a, each of the shearing members 100, 102 has a radialdimension sufficient to bring its respective inner face 110, 120 intoclose proximity with an adjacent rotating element. That is, the innerface 110 of the distal shearing member 100 is spaced across a gap 130from the body 56 of the rotatable member 34. Similarly, the inner face120 of the proximal shearing member 102 is spaced across a gap 132 fromthe drive shaft 22. The gaps 130 and 132 are preferably minimizedwithout risking contact between the respective rotating element andshearing member. Illustrative numerical ranges are presented herewith,and will be known by artisans to be exemplary and not limiting. Morespecifically, the gaps 130 and 132 are each desirably greater than zerobut less than 0.254 mm (0.01 inches). More preferably, the gaps 130 and132 are each less than 0.0254 mm (0.001 inches), and most preferably thegaps are each less than 0.0127 mm (0.0005 inches).

Each of the inner faces 110, 120 of the shearing members 100, 102preferably has an arcuate surface concentric with the axis of rotationof the adjacent rotating element. In addition, the inner faces 110, 120preferably have a radius of curvature that corresponds to the adjacentrotating elements. Namely, the distal shearing member 100 has an innerface 110 that is the same radius of curvature as the body 56 of therotatable member 34, and the inner face 120 of the proximal shearingmember 102 has a curvature that is the same as the external diameter ofthe drive shaft 22. In one embodiment, merely offered for considerationas an illustration of the teachings of the present invention, the radiusof curvature of the inner face 110 is about 1.194 mm (0.047 inches), andthe radius of curvature of the inner face 120 is about 0.991 mm (0.039inches).

As illustrated in FIG. 2b, the distal shearing member 100 is oriented180 degrees about the housing 32 with respect to the proximal shearingmember 102. In practice, the relative orientation of the shearingmembers 100, 102 about the housing 32 is not considered especiallysignificant. Therefore, the shearing members 100, 102 may be axiallyaligned, or offset with respect to one another around the circumferenceof the housing 32 at any relative orientation.

The axial and circumferential dimensions of each of the shearing members100, 102 must be sufficient to provide adequate strength withoutinordinately blocking the lumen 40 through the housing 32. In oneembodiment, for example, it has been discovered that the distal lumen 42has a diameter of approximately 1.75 mm (0.069 inches), and the distalshearing member 100 has an axial dimension of approximately 0.279 mm(0.011 inches) and an included angle of approximately 25 degrees. In thesame embodiment, the proximal lumen 44 has a diameter of approximately1.42 mm (0.056 inches), and the proximal shearing member 102 has anaxial dimension of approximately 0.318 mm (0.0125 inches) and anincluded angle about of 25 degrees. Relative measurements anddimensional sizing, are included merely to demonstrate utility of theinstant teachings, and are not intended to limit them.

In use, the material removal tip 30 is inserted into a body vessel orother cavity using the aforementioned guidewire 28 and conventionalcatheter introduction techniques not described further herein. Thedistal tip 30 is manipulated into close proximity with the targetblockage or material deposit, the drive shaft 22 rotated, and the vacuumsource 20 actuated. As the distal tip 30 is advanced toward the materialto be removed, the suction created at the mouth 82 tends to pullmaterial into contact with the rotatable member 34 and screw thread 58.The combination of suction and “Archimedes Screw” action of the screwthread 58 draws material into the distal housing section 36, andultimately into contact with the rotating flanges 66. As the material isdrawn through the distal housing section 36, the screw thread 58performs a coarse chopping, reducing the largest material agglomerationsin size. Subsequently, the rotating flanges 66 more finely chop thematerial to reduce clogging of the tubular passageway between the driveshaft 22 and first the proximal lumen 44 and then the inner surface ofthe elongated tube 12.

It has been found that without a shearing member, such as provided bythe distal and proximal members 100, 102, material tends to build up onthe axially-facing surfaces of the flanges 66. Eventually, buildup ofmaterial occludes the circumferential spaces between the flanges 66,greatly diminishing the capacity of material removal, and in someinstances irreversibly clogging the device. Consequently, the presentinvention provides one or more shearing members to cut or otherwiseknock material from the axially facing surfaces of the rotating flanges66. Because of the relative movement between the flanges 66 and shearingmembers 100, 102, the discontinuous circumferential projection of theshearing members, and the close axial spacing between these relativelymoving surfaces, material is effectively sheared from the axially facingsurfaces of the flanges 66. Any material sheared from the flanges 66 isthen exhausted in a proximal direction through the annular passageway 24within the elongated tube 12. The flanges 66 are thus maintained clearof material, and their corners thus remain unobstructed and effective infinely chopping the material that reaches them.

With reference to FIGS. 3 and 4, the proximal face 104 of the distalshearing member 100 and the distal face 106 of the proximal shearingmember 102 are preferably oriented normal to the axis of rotation 37 ofthe member 34. In addition, the transition surfaces 114, 124 arepreferably axially oriented. As seen in FIGS. 2c and 2 d, therefore, thecross-sections (taken circumferentially) of the shearing members 100,102 are rectangular, and shearing edges 116, 126 are defined byperpendicular corners that face the leading edges of the oncomingflanges 66. The leading edges of each of the flanges 66 are likewisedefined by perpendicular corners 68 so that the passage of the flanges66 past the shearing members 100, 102 creates a scissor-like action,serving not only to clear material from the axial surfaces of theflanges 66 but also to sever fibrous matter present in any materialcaught therebetween. Alternatively, one or both of the cooperating edgeson the flanges 66 and shearing members 100, 102 may be sharpened toknife edges to further facilitate the severing action, although theremay be a limit to such sharpening dictated by strength considerations.FIG. 2c shows one flange 66 having material adhered thereto andapproaching the proximal shearing member 102, while FIG. 2d showsanother flange 66 having just passed the distal shearing member 100 andbeen cleared of material.

To further facilitate the two functions of the shearing members 100, 102(i.e., clearing material from the axial surfaces of the flanges 66 andalso severing fibrous matter), the transition surfaces 114, 124 eachhave a radial portion that gradually transitions to blend into the baselumen wall, as seen in FIGS. 3b and 4 b. That is, the transition surface114 gradually curves into tangency with the wall of the distal lumen 42,and the transition surface 124 gradually curves into tangency with thewall of the proximal lumen 44. The curvilinear transition surfaces 114,124 thus provide a radial shear component between the respectiveshearing edges 116, 126 and leading edges 68 of the rotating flanges 66.It will be clear, therefore, that the shearing action is scissor-like(as opposed to unidirectional shear) as the oncoming leading edge 68 ofeach flange 66 first reaches the radially outermost portion of eachshearing edge 116 or 126, and then gradually reaches the rest of theshearing edge. This is preferred over a situation where the flangeleading edge 68 reaches the entire shearing edge at once, which would bethe case if the surfaces 114, 124 were entirely radially disposed. Ofcourse, the latter arrangement is not precluded while still obtainingmost of the benefits of the present invention.

As mentioned above, various other configurations of the material removaltip 30 are contemplated. For example, FIGS. 5-6 illustrate a materialremoval tip 150 having a one-piece housing 152 and a single shearingmember 154. As before, the housing 152 includes a distal section 160, aproximal section 162, a distal lumen 164, a proximal lumen 166, and anintermediate groove 168. Likewise, the rotating member 170, identical tothe member 34 previously described, includes outwardly projectingflanges 172 that are axially restrained within the groove 168. Theelongated tube and drive shaft are not shown in FIG. 5a for clarity.

As seen best in FIGS. 6a and 6 b, the shearing member 154 is locatedjust proximal to the groove 168, and thus corresponds to the proximalshearing member 102 described for the first embodiment. There is nodistal shearing member in this embodiment. It all other aspects, theshearing member 154 is identical to the proximal shearing member 102described above, and includes an arcuate inner face 174 spanning anincluded angle 176, transition surfaces 178, and a distal face 180coincident with the proximal boundary of the groove 168. The distal face180 is thus axially adjacent the rotating flanges 172 and serves toknock material from the proximal faces of the flanges.

Although only one shearing member is shown located either distally orproximally with respect to the groove, those skilled in the art willrecognize that two or more shearing members on either side can also beprovided. It has been found that a single shearing member is sufficientto knock material from the axially facing surfaces of the flanges, andis preferred because it minimizes the obstruction to flow of materialfrom the distal to the proximal sections of the housing. Likewise, asmentioned above, a shearing member provided of only one side of therotating flanges is believed to significantly improve performance of thedevice. Thus, as seen in FIGS. 5-6, a single shearing member 154 isprovided proximal to the rotating flanges 172, and another alternativenot illustrated is a single shearing member located distally withrespect to the flanges.

A still further embodiment of the present invention is seen in FIGS. 7aand 7 b. In these views, an alternative one-piece housing 200 is shownfor use with a rotating member, such as the members 34 or 170 describedpreviously. Again, the housing 200 includes a distal section 202, aproximal section 204, a distal lumen 206, a proximal lumen 208, and anintermediate groove 210. A distal shearing member 220 and a proximalshearing member 222 are located on opposite sides and adjacent to thegroove 210. The shearing members 220 and 222 are alignedcircumferentially, as seen in the end view of FIG. 7b.

The choice of using a one- or two-piece housing depends upon themanufacturing choices available. A one-piece housing is preferred iftooling for forming the shearing members 220, 222 on the inner surfacethereof is really available. On the other hand, forming the innershearing members on the mating ends of each section of a two-piecehousing is somewhat easier, and the two sections can then be joined andwelded or otherwise fastened together.

A number of different materials are suitable for the material removaldevice, including stainless-steel, titanium, acrylic or other suitablebiocompatible and rigid materials. The selection of material may bedictated by the particular manufacturing process used. In a preferredembodiment, the material removal device housing is formed in twosections of stainless-steel and includes a single shearing member oneach side of the rotating flanges. The two sections are preferably laserwelded together.

Another embodiment is shown in FIG. 8A and FIG. 8B, wherein therotatable member of the invention includes a grinder rotor 300 forgrinding material between abrasive surface 320 on the grinder rotor andabrasive surface 310 in the housing of the device. This embodiment mayfurther include at least one cutting flute 330 to aid the grinding. Inthe embodiment shown in FIG. 8A and FIG. 8B, grinding of the materialtakes place prior to contact of the material with the shearing member.Abrasive surfaces 310 and 320 may be fabricated from one or moreabrasive materials such as ceramics, diamond, quartz, silicon carbide,aluminum oxide, boron carbide, boron nitride, tungsten carbide andtitanium nitride. Alternatively, abrasive surfaces 310 and 320 can betitanium or stainless steel surfaces with a ridged, file-like surface.

Stated briefly, the various embodiments of the invention include amethod of removing material from a body lumen in a patient in need ofsuch removal, comprising advancing a catheter-mounted device having adistal material removal tip including a hollow housing and a memberrotatable therewithin, rotating the rotatable member, drawing thematerial into the housing, shearing the material in the housing betweenrelatively rotating shearing members to reduce the clogging propensityof the material, removing the sheared material from within the housingas the material removal tip is advanced through the vessel.

The method may further include first coarsely chopping the material inthe housing, and then finely chopping the material in the housing duringthe step of shearing.

In another embodiment of the invention, the method utilizes a rotatablemember that includes a screw thread. Here, the step of coarsely choppingthe material in the housing is accomplished by contact between the screwthread and the material. In another embodiment of the method, the stepof shearing includes cutting material in a scissor-like manner betweenopposed shearing edges provided on the relatively rotating shearingmembers. Here, the opposed shearing edges define shearing planes forsimultaneous coarse, medium and fine shearing, wherein the shearingplanes comprise a range of dimensions up to about 0.05 mm (about 0.002inches).

The method may involve a catheter-mounted device having a distalmaterial removal tip that has a total preselected diameter effective foruse in a preselected body lumen, which may be a blood vessel, a lumenfor the passage of bile, a lumen for the passage of urine, a lymphvessel, a gastrointestinal lumen, and the like.

Still another embodiment involves a method of removing material from andtreating a body lumen with a medically useful agent in a patient in needof such removal and treatment, comprising advancing a catheter-mounteddevice having a distal material removal tip including a hollow housingand a member rotatable therewithin, the device further comprising alumen, wherein the lumen is adapted to contain a medically useful agentfor release at a predetermined time; rotating the rotatable member,drawing material into the housing, shearing the material in the housingbetween relatively rotating shearing members to reduce the cloggingpropensity of the material, removing the sheared material from withinthe housing as the material removal tip is advanced through the vessel;and, releasing the medically useful agent at the predetermined time. Therelease may be accomplished by pumping means, such as gas pressure,mechanical pressure, liquid pressure, and the like. The medically usefulagent may be an x-ray contrast agent, a thrombolytic agent, a viralvector, an enzyme such as a proteolytic enzyme, and the like.

In another embodiment of the method, portions of the shearing membersare coated or fabricated using ceramics, diamond, quartz, siliconcarbide, aluminum oxide, boron carbide, boron nitride, tungsten carbide,titanium nitride and the like, whereas the rotatable member and tubularhousing are constructed using stainless steel, titanium, acrylic plasticand the like biocompatible materials.

In another embodiment, the invention teaches a method of removingmaterial from a body lumen in a patient in need of such removal,comprising advancing a catheter-mounted device having a distal materialremoval tip including a hollow housing and a member rotatabletherewithin, wherein the rotatable member includes grinding means forgrinding the material, rotating the rotatable member, grinding thematerial into ground material, drawing the ground material into thehousing, shearing the material in the housing between relativelyrotating shearing members to reduce the clogging propensity of thematerial, removing the sheared material from within the housing as thematerial removal tip is advanced through the vessel. The grinding meansmay be fabricated from such abrasive materials as ceramics, diamond,quartz, silicon carbide, aluminum oxide, boron carbide, boron nitride,tungsten carbide, titanium nitride, and the like, including interactivemedia.

In another embodiment, the invention provides an article of manufacture,comprising packaging material and instructional material for the use ofthe method. The article of manufacture may further include percutaneousmaterial removal devices, guidewires, introducers, containers,catheters, angioplasty balloons, stents, medicinal agents, medicalsyringes, and the like. The instructional material may include printedmaterials, GD disks, magnetic data storage disks, videotapes, and thelike.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges that come within the meaning and range of equivalency of theclaims are to be embraced within their scope, as if the same wereliterally set forth herein.

What is claimed is:
 1. A method of removing material from a body lumenin a patient, the method comprising: advancing through said body lumen acatheter-mounted device having a distal material removal tip comprisinga hollow housing, a member rotatable therewithin, and a shearing member;rotating the rotatable member; drawing said material into said housing;shearing said material in said housing between said rotating rotatablemember and the shearing member, whereby the propensity of said materialto clog said device is reduced; and removing said material from withinsaid housing as said material removal tip is advanced through said bodylumen.
 2. The method of claim 1, further including: first coarselychopping said material in said housing; and then, finely chopping saidmaterial in said housing during said step of shearing.
 3. The method ofclaim 2, wherein said rotatable member includes a screw thread and saidstep of coarsely chopping said material in said housing is accomplishedby contact between said screw thread and said material.
 4. The method ofclaim 1, wherein the shearing member comprises opposed shearing edgesand the step of shearing the material includes cutting the material in ascissor-like manner between the opposed shearing edges.
 5. The method ofclaim 4, wherein said opposed shearing edges define shearing planes forsimultaneous coarse, medium and fine cutting.
 6. The method of claim 5,wherein said opposed shearing edges define said shearing planescomprising a range of dimensions up to about 0.05 mm (about 0.002inches) for simultaneous coarse, medium and fine shearing.
 7. The methodof claim 1 wherein said catheter-mounted device having a distal materialremoval tip has a total preselected diameter effective for use in saidpreselected body lumen.
 8. The method of claim 7 wherein saidpreselected body lumen is selected from the group consisting of bloodvessels, lymph vessels, lumens for the passage of bile, lumens for thepassage of urine, and gastrointestinal lumens.
 9. The method of claim 1wherein said catheter-mounted device further comprises a device lumenadapted to release a medically useful agent, the method furthercomprising: releasing said medically useful agent into said body lumenfrom said device lumen.
 10. The method of claim 9, wherein said releaseis accomplished by pumping means.
 11. The method of claim 10, whereinsaid pumping means is selected from the group consisting of gaspressure, mechanical pressure, and liquid pressure.
 12. The method ofclaim 9, wherein said medically useful agent is an x-ray contrast agent.13. The method of claim 9, wherein said medically useful agent is athrombolytic agent.
 14. The method of claim 9, wherein said medicallyuseful agent is a viral vector agent.
 15. The method of claim 9, whereinsaid medically useful agent is an enzyme.
 16. The method of claim 9,wherein said enzyme is a proteolytic enzyme.
 17. The method of claim 1,wherein portions of said shearing member are coated with at least onematerial selected from the group consisting of ceramics, diamond,quartz, silicon carbide, aluminum oxide, boron carbide, boron nitride,tungsten carbide and titanium nitride.
 18. The method of claim 1,wherein portions of said shearing members are fabricated from at leastone material selected from the group consisting of ceramics, diamond,quartz, silicon carbide, aluminum oxide, boron carbide, boron nitride,tungsten carbide and titanium nitride.
 19. The method of claim 1,wherein said rotatable member and said generally tubular housing areconstructed substantially of at least one material selected from thegroup consisting of stainless steel, titanium, and acrylic plastic. 20.An article of manufacture, comprising packaging material andinstructional material for the use of the method of claim
 1. 21. Thearticle of manufacture of claim 20, further including at least one itemselected from the group consisting of percutaneous material removaldevices, guidewires, introducers, containers, catheters, angioplastyballoons, stents, medicinal agents, and medical syringes.
 22. Thearticle of manufacture of claim 20, wherein said instructional materialis at least one device selected from the group consisting of printedmaterials, CD disks, magnetic data storage disks, and videotapes.
 23. Amethod of removing material from a preselected body lumen in a patientin need of such removal, comprising: advancing through said preselectedbody lumen a catheter-mounted device having a distal material removaltip including a hollow housing, a shearing member and a member rotatabletherewithin, wherein said rotatable member includes grinding means forgrinding said material prior to said contact of said material with saidshearing member, wherein said grinding means include at least oneabrasive surface fabricated from at least one abrasive material selectedfrom the group consisting of ceramics, diamond, quartz, silicon carbide,aluminum oxide, boron carbide, boron nitride, tungsten carbide, titaniumnitride, titanium surfaces with a file-like surface, and stainless steelsurfaces with a file-like surface; rotating said rotatable member;grinding said material into ground material; drawing said groundmaterial into said housing; shearing said material in said housingbetween the rotating rotatable member and shearing member, whereby thepropensity of said material to clog said device is reduced; and removingsaid material from within said housing as said material removal tip isadvanced through said preselected body lumen.
 24. The method of claim23, wherein said rotatable member includes a grinder rotor having atleast a first abrasive surface, and said housing includes at least asecond abrasive surface.